WhatsApp is a simple way to message for free.

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There's a reason Facebook acquired WhatsApp for $19 billion earlier this year, and that's because WhatsApp is exactly what every messaging app should aim to be. It's designed well, free to use (even for international messaging), has a thriving user base, and lets you send texts, voice messages, pictures, and videos.

Vine is a creative way to share 6-second looping videos.

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Vine lets you splice together clips that play on a loop and share them with your friends. You can edit videos on the spot and post to Twitter and Facebook, and you can now import videos from your phone, too. The community also allows you to find, follow, and interact with other Vine users.

Snapchat is the best photo messaging app out there.

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Snapchat began as just an app for sharing self-destructing photos and videos to your friends, but it's quickly evolved into the No. 1 app for visual communication. With its new Stories feature, you can now weave together photos and videos into a visual status of sorts, and you can also send texts from directly within the app.

Secret is a social message for saying what's really on your mind.

Secret lets you and your friends speak freely with each other and the world, but you'll never know whose secret you're reading. People post and comment anonymously, and you can now easily ask "Yes or No" questions that people can respond to. To help make the text-based posts more beautiful, Secret now gives you access to Flickr's photo library for background images.

There's no better place to share photos than Instagram.

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Instagram is one of our favorite iPhone apps of all time. With over 200 million users and host of photo-editing filters, it's a great place to show off your artistic side and share some photos of your own.

The official Twitter app is a great way to keep up with your tweets on the go.

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Twitter's official app lets you stay on top of your tweets from your phone. Besides that, it offers some unique features that aren't found in third-party apps. For example, you can set specific push notifications for individual accounts so you'll never miss an important bit of news.

Update your blog on the go with Tumblr.

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Tumblr lets you follow blogs and create simple updates via text, audio, photos, quotes, and video. It's a great way to seamlessly manage your blog while also seeing what other people are interested in.

LinkedIn is the best network out there for managing your professional connections.

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With over 300 million users, LinkedIn is a great place to network and connect with other professionals. The app is well-designed, syncs with your phone's calendar to help stay on top of meetings, and even lets you view and save recommended jobs. If you're a Premium subscriber, you can also see who has viewed your profile every day, right from your phone's Notification Center.

Stay in touch with your friends and family wherever you are with Facebook.

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Facebook is still the best social network out there for staying in contact with those you care about. Besides letting you see what your friends are up to, you can share updates, photos, and videos on the go, and push notifications quickly alert you to any activity that involves you. You can also play games and use your favorite Facebook apps.

TapTalk makes it easy to send photos and videos to your friends with a lightning-fast interface.

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TapTalk is a personal messaging app that's all about speed. By arranging your friend icons in a grid-like layout, you can quickly tap their picture to capture a photo. To send a video, just hold down their icon to record, and release when you're done.

Facebook Messenger is great for reaching out to your Facebook friends.

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Facebook Messenger handles all your real-time communications on Facebook. You can message your friends, send pictures and videos, and even call them over WiFi or your data plan when you're out and about.

Facebook is in the process of spinning out Messenger from the regular Facebook app. Soon, it'll be the only way you can send Facebook messages on mobile.

Pinterest is perfect for sharing photos of your interests with your friends.

Pinterest

Pinterest encourages you to find things you're interested in and "pin" them to your virtual pinboard, which acts like your own creative collage. Friends and those who follow you can then comment on your pinboard or re-pin a photo, and if you're using an iPhone, you can pin an item directly from within the Safari web browser.

Hinge/Tinder/Grindr/OkCupid are the next generation of dating apps.

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Meeting people has never been easier with these four apps.

Hinge: Hinge helps you discover people that your Facebook friends already know, requiring a Facebook account so you can view the interesting details about a person while removing the "random" aspect of other dating apps. You get to see a curated list of potential matches, and select those you're interested in. If someone "likes" you back, Hinge introduces the two of you to help get the conversation started.

Tinder: Tinder is best known for its swiping system, which lets you swipe right if you're interested in someone or left to move on to your next potential match. If two people both swipe right on each other, Tinder lets you know you have a match, and you can message your match from right within the app.

Grindr: Grindr is a location-based dating app targeted towards gay and bisexual men. The app lets you know what singles are nearby so you can meet up with them, and with over 5 million active monthly users, there are plenty of choices.

OkCupid: OkCupid has most of the same features as other social networks. Users can chat, send status updates, message potential matches, and let the service match you up using its algorithms. The mobile app also lets you know what singles are nearby for impromptu meetups.